Elizabeth Day’s first novel, “Scissors, Paper, Stone,” a taut, beautifully written drama, won a Betty Trask award. It was about a mother and a daughter who were holding things together by keeping a secret. This, the writer’s second novel, has a similarly claustrophobic atmosphere. Unspoken truths threaten to pull apart one family’s illusions about itself.

On the surface, this is the story of the tension between a married couple and the mother-in-law. But there’s a fourth character, painfully missing. Max, the 21-year-old only son of Caroline and Andrew, has been killed by a land mine while on service in Central Africa. His parents are barely emerging from their grief only a few months later when they have to face the fact that Andrew’s mother, Elsa, can no longer cope alone and needs to come and live with them.

This is especially difficult for Caroline. She has always felt inferior to Elsa, suspecting that her mother-in-law wishes someone as common as Caroline had never married her precious son.

It’s poignant — and amusing — that both Caroline and Elsa share the same problem: They are more in love with their child than with anyone else. But it’s not something they can bond over. And in any case, no one can understand what Elsa is saying any more. Which at least might make her easier for Caroline to live with.

The story is told from the perspective of the three main characters, so we get a window into all their different worlds. We experience Elsa’s senility as she experiences it. She sees and hears things exactly as they are but is unable to make others understand her. As a result, she is increasingly retreating into memories of her childhood, which only serve to make her more frightened.

Day’s great strength is her insight. Her characters are difficult and often unpleasant. But they are all the more real for that. And while they may dislike one another, be unable to get along and do things that are hard to forgive in real life, in this fictional universe we identify with them and understand how things have come to this.

I really enjoyed the interplay between the different generations. Elsa is still haunted by the hideous yellow mini-dress Caroline wore on the first day Andrew brought her home to meet his mother.

Thirty years later, Caroline makes the opposite mistake by trying to be best mates with Max’s friends by letting them smoke around her. Andrew, meanwhile, tries to keep the memory of his son alive by embarking on a liaison with a woman who is far closer to Max’s age.

The themes of war and grief loom large. We know from the outset that Elsa has been scarred by her father’s experiences in World War I. He returned barely able to talk or interact with anyone.

And yet Elsa is the first to encourage Max to become a soldier — for which Caroline can’t forgive her.

The family dysfunction and refusal to face the truths of the past are mixed with flashes of humor. This is an elegant, addictive portrayal of a family at war with its past. A beautifully written novel whose quietly discomfiting tone stays with you for a long while afterwards.